[Data] Log full tracebacks in tests (#46101)

#43251 added a feature where Ray Data doesn't print internal stack traces to make errors easier to read for users. However, this information is useful for development, so this PR disables the feature in CI.

Signed-off-by: Balaji Veeramani <[email protected]>

python/ray/data/exceptions.py

@@ -52,7 +52,7 @@ def handle_trace(*args, **kwargs):
             # via DataContext, or when the Ray Debugger is enabled.
             # The full stack trace will always be emitted to the Ray Data log file.
             log_to_stdout = DataContext.get_current().log_internal_stack_trace_to_stdout
-            if _is_ray_debugger_enabled() or log_to_stdout:
+            if _is_ray_debugger_enabled():
                 logger.exception("Full stack trace:")
                 raise e
 

python/ray/data/tests/conftest.py

@@ -775,3 +775,8 @@ def _assert(last_snapshot):
     )
 
     return last_snapshot
+
+
+@pytest.fixture(autouse=True, scope="function")
+def log_internal_stack_trace_to_stdout(restore_data_context):
+    ray.data.context.DataContext.get_current().log_internal_stack_trace_to_stdout = True